In general, a Base Station (BS) receives information on intensities of signals, intensities of interference signals from adjacent cells, and a data rate from User Equipments (UEs) located at cell edges and controls transmission power of each cell based on the received information.
By using a transmission power control technology, throughput of the UEs located at the cell edges currently in an in-service state can be improved. However, since a conventional transmission power control technology does not consider a cell outage detection and a cell outage compensation at all, a cell coverage in an out-of-service state cannot be controlled.
Meanwhile, in order to guarantee service quality, a network operator performs a process of optimizing a coverage to resolve the cell outage when installing a system. The cell outage occurs when an intensity of a received signal from a serving cell is low or intensities of interference signals from adjacent cells are high. Accordingly, by controlling transmission power of the cell, a problem of the cell outage can be solved. To solve the problem, at present, cell outage related information such as a position where the cell outage is generated and an intensity of a received signal is collected in a passive manner such as a drive test and transmission power of cells located at an area where the cell outage is generated based on the collected information. The process of optimizing the cell coverage is passively performed, thereby requiring a lot of time and human resources. Accordingly, the process is inefficient and its capability is also unsatisfactory. Therefore, a method is needed in which the system automatically controls the transmission power of the cell by detecting and compensating for the cell outage.